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etcd实现Docker多机容通信
1. 实验准备
准备两台可以相互通信的linux主机，并安装好docker。本实验准备的两台主机ip分别为：172.28.65.114和172.28.65.126
2. 搭建etcd集群
etcd是开源免费的分布式存储工具，官网 https://coreos.com/etcd.
在两台机器上分别装上etcd
172.28.65.114上
// 下载etcd
[root@eshop-cache04 opt]# wget https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz
// 解压
[root@eshop-cache04 opt]# tar zxvf etcd-v3.0.12-linux-amd64.tar.gz
//进入目录
[root@eshop-cache04 opt]# cd etcd-v3.0.12-linux-amd64
//安装etcd
[root@eshop-cache04 etcd-v3.0.12-linux-amd64]# nohup ./etcd --name docker-node1 --initial-advertise-peer-urls http://172.28.65.114:2380 \
--listen-peer-urls http://172.28.65.114:2380 \
--listen-client-urls http://172.28.65.114:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://172.28.65.114:2379 \
--initial-cluster-token etcd-cluster \
--initial-cluster docker-node1=http://172.28.65.114:2380,docker-node2=http://172.28.65.126:2380 \
--initial-cluster-state new&
172.28.65.126上
// 下载etcd
[root@eshop-cache04 opt]# wget https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz
// 解压
[root@eshop-cache04 opt]# tar zxvf etcd-v3.0.12-linux-amd64.tar.gz
//进入目录
[root@eshop-cache04 opt]# cd etcd-v3.0.12-linux-amd64
//安装etcd
[root@eshop-cache04 etcd-v3.0.12-linux-amd64]# nohup ./etcd --name docker-node2 --initial-advertise-peer-urls http://172.28.65.126:2380 \
--listen-peer-urls http://172.28.65.126:2380 \
--listen-client-urls http://172.28.65.126:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://172.28.65.126:2379 \
--initial-cluster-token etcd-cluster \
--initial-cluster docker-node1=http://172.28.65.114:2380,docker-node2=http://172.28.65.126:2380 \
--initial-cluster-state new&
检查cluster状态
[root@eshop-cache05 etcd-v3.0.12-linux-amd64]# ./etcdctl cluster-health
cluster may be unhealthy: failed to list members
Error: client: etcd cluster is unavailable or misconfigured
error #0: dial tcp 127.0.0.1:4001: getsockopt: connection refused
error #1: client: endpoint http://127.0.0.1:2379 exceeded header timeout
检查是防火墙已开启，关闭防火墙，再查看cluster状态
[root@eshop-cache05 etcd-v3.0.12-linux-amd64]# sudo systemctl stop firewalld
[root@eshop-cache05 etcd-v3.0.12-linux-amd64]# ./etcdctl cluster-health
member 3769a4d777a29309 is healthy: got healthy result from http://172.28.65.126:2379
member 4ac06614f93070c0 is healthy: got healthy result from http://172.28.65.114:2379
cluster is healthy
至此，etcd集群搭建成功。
3. 重启docker服务
172.28.65.114上，停止docker服务
$ service docker stop
启动docker
$ /usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock --cluster-store=etcd://172.28.65.114:2379 --cluster-advertise=172.28.65.114:2375&
172.28.65.126上，停止docker服务
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$ service docker stop
启动docker
$ /usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock --cluster-store=etcd://172.28.65.126:2379 --cluster-advertise=172.28.65.126:2375&
4. 创建overlay
在172.28.65.114上创建overlay
$ docker network create -d overlay demo
查看network
172.28.65.114上
[root@eshop-cache04 opt]# docker network ls
NETWORK ID NAME DRIVER SCOPE
1570c6f0cf99 bridge bridge local
b9861814863a demo overlay global
b9941cbbb213 host host local
977e41d92f6d none null local
172.28.65.126上
[root@eshop-cache05 opt]# docker network ls
NETWORK ID NAME DRIVER SCOPE
750012e174af bridge bridge local
b9861814863a demo overlay global
dbbce56b6248 host host local
7a061d72a8e4 none null local
查看创建的网络模式demo
[root@eshop-cache05 opt]# docker network inspect demo
[
{
"Name": "demo",
"Id": "b9861814863a4b3ce7f8d80414612bd77d3755d59c995334ad70b3981e86282b",
"Created": "2019-01-08T08:04:21.9061569-05:00",
"Scope": "global",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": {},
"Config": [
{
"Subnet": "10.0.0.0/24",
"Gateway": "10.0.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {},
"Labels": {}
}
]
5. 实验
5.1 创建两个busybox容器
172.28.65.114上
[root@eshop-cache04 opt]# sudo docker run -d --name test1 --net demo busybox sh -c "while true; do sleep 3600; done"
172.28.65.126上
[root@eshop-cache05 opt]# docker run -d --name test1 --net demo busybox sh -c "while true; do sleep 3600; done"Unable to find image 'busybox:latest' locally
latest: Pulling from library/busybox
57c14dd66db0: Pull complete
Digest: sha256:7964ad52e396a6e045c39b5a44438424ac52e12e4d5a25d94895f2058cb863a0
Status: Downloaded newer image for busybox:latest
b7d4a8a3c5c9e46986346614f210ea1b1e16669d30450a2e7bc79e6f8ce3d9ea
docker: Error response from daemon: endpoint with name test1 already exists in network demo.
[root@eshop-cache05 opt]# docker run -d --name test2 --net demo busybox sh -c "while true; do sleep 3600; done
5.2 验证连通性
172.28.65.114上网络状态
[root@eshop-cache04 opt]# docker exec test1 ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:0A:00:00:02
inet addr:10.0.0.2 Bcast:10.0.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1450 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
eth1 Link encap:Ethernet HWaddr 02:42:AC:12:00:02
inet addr:172.18.0.2 Bcast:172.18.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:14 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1116 (1.0 KiB) TX bytes:0 (0.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
172.28.65.126上网络状态
[root@eshop-cache05 opt]# sudo docker exec -it test2 ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:0A:00:00:03
inet addr:10.0.0.3 Bcast:10.0.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1450 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
eth1 Link encap:Ethernet HWaddr 02:42:AC:13:00:02
inet addr:172.19.0.2 Bcast:172.19.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:16 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1248 (1.2 KiB) TX bytes:0 (0.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
在172.28.65.114上执行命令，可以ping通172.28.65.126上创建的busybox(10.0.0.3)容器
[root@eshop-cache04 opt]# sudo docker exec test1 sh -c "ping 10.0.0.3"
PING 10.0.0.3 (10.0.0.3): 56 data bytes
64 bytes from 10.0.0.3: seq=0 ttl=64 time=6.775 ms
64 bytes from 10.0.0.3: seq=1 ttl=64 time=0.458 ms
64 bytes from 10.0.0.3: seq=2 ttl=64 time=0.401 ms
64 bytes from 10.0.0.3: seq=3 ttl=64 time=0.405 ms
64 bytes from 10.0.0.3: seq=4 ttl=64 time=0.395 ms
^Z
[1]+ Stopped sudo docker exec test1 sh -c "ping 10.0.0.3"